Apparatus and method for retrieval of downhole sample

ABSTRACT

Disclosed is an apparatus for retrieving a downhole sample. The apparatus includes: a carrier configured to be conveyed through a borehole penetrating an earth formation; a sample capsule configured to be disposed at the carrier and to contain the sample; and a discharge mechanism configured to discharge the sample capsule downhole into drilling fluid in the borehole.

BACKGROUND

Boreholes are drilled deep into the earth for many applications such as carbon dioxide sequestration, geothermal production, and hydrocarbon exploration and production. A sample tool may be conveyed through a borehole in order to take a sample of a formation fluid. In an operation referred to as logging-while-drilling, the sample tool is disposed in a bottom hole assembly (BHA) and conveyed through the borehole by a drill string while the borehole is being drilled. During a temporary halt in drilling, the sample may be extracted from the wall of the borehole penetrating a formation containing the fluid. When the drill string and thus the BHA are removed from the borehole, the sample is retrieved from the tool and then analyzed. Unfortunately, when the drill string is being removed from the borehole, the borehole cannot be further drilled at that time leading to an inefficient use of drilling resources. In addition, analysts will have to wait a considerable amount of time to receive the sample. Hence, it would be well received in the drilling industry if the retrieval times for downhole samples could be improved.

BRIEF SUMMARY

Disclosed is an apparatus for retrieving a downhole sample. The apparatus includes: a carrier configured to be conveyed through a borehole penetrating an earth formation; a sample capsule configured to be disposed at the carrier and to contain the sample; and a discharge mechanism configured to discharge the sample capsule downhole into drilling fluid in the borehole.

Also disclosed is a method for retrieving a downhole sample. The method includes: conveying a carrier through a borehole penetrating an earth formation; extracting a sample from the earth formation with a sampling tool disposed at the carrier; disposing the sample in a sample capsule; and releasing the sample capsule into drilling fluid in the borehole using a capsule discharge mechanism.

BRIEF DESCRIPTION OF THE DRAWINGS

The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:

FIG. 1 illustrates an exemplary embodiment of a drill string disposed in a borehole penetrating the earth;

FIG. 2 depicts aspects of a bottom hole assembly disposed at a distal end of the drill string;

FIG. 3 depicts aspects of a bottom hole assembly having a plurality of sample capsules; and

FIG. 4 presents one example of a method for retrieving a downhole sample.

DETAILED DESCRIPTION

A detailed description of one or more embodiments of the disclosed apparatus and method presented herein by way of exemplification and not limitation with reference to the Figures.

FIG. 1 illustrates an exemplary embodiment of a drill string 10 disposed in a borehole 2 penetrating the earth 3, which includes an earth formation 4. A drill string rotation system 5 disposed at a drill rig 19 at the surface of the earth 3 is configured to rotate the drill string 10 in order to rotate a drill bit 6 disposed at a distal end of the drill string 10. The drill bit 6 represents any cutting device configured to cut through the earth 3 or rock in the formation 4 in order to drill the borehole 2. Disposed adjacent to the drill bit 6 is a bottom hole assembly (BHA) 7. The drill bit 6 can be included in the BHA 7 or it can be separate from it. The BHA 7 can include downhole components such as a downhole tool and a mud motor. In order to cool and lubricate the drill bit 6 and flush cuttings from the borehole 2, drill fluid 13 is pumped downhole through the interior of the drill string 10 from which it exits the drill bit 6. The drilling fluid then returns to the drill rig 19 via an annulus 14 surrounding the BHA 7 and the drill string 10 within the borehole 2.

Still referring to FIG. 1, a sample tool 8 is disposed at the BHA 7 and configured to extract a formation sample during a temporary halt in drilling. The sample tool 8 includes an extendable probe 11 configured to extend from the BHA 7 and seal to the borehole wall. An optional brace 17 may be used to hold the BHA 7 in place while the sample is being taken. A pump 12 is configured to lower pressure in the probe 11 to pump a sample of formation fluid from the formation 4 and into the sample tool 8. From the sample tool 8, the sample is disposed into a sample capsule 9 configured for transit to the surface of the earth by the drilling fluid 13 in the annulus 14. At the surface of the earth 3, the sample capsule 9 is retrieved from the drilling fluid 13 by a sample capsule catcher 15. In one or more embodiments, the sample capsule catcher 15 includes a screen having a mesh size small enough to catch the sample capsule 9.

In many cases, it is desired to analyze the retrieved sample at the ambient conditions, such as pressure and temperature, at which the sample was obtained. Hence, in one or more embodiments, the sample capsule 9 has a wall thickness sufficient to contain the sample at the pressure when the sample was extracted. To maintain the sample at the extracted temperature, the sample capsule 9 includes insulation 18. In one or more embodiments, an actuator 91 is disposed in the sample capsule 9 as illustrated in FIG. 1. The actuator 91 is configured to actively maintain the thermal (e.g., temperature) and/or physical (e.g., pressure) conditions at which the sample was obtained. Alternatively, the actuator 91 can be configured to maintain the sample at selected conditions. In one or more non-limiting embodiments, the actuator 91 includes a heating element configured to add heat to the sample to maintain the sample at the extracted temperature or a selected temperature. A power source (not shown) such as battery or a device configured to harvest energy from surrounding media can be used to power the heating element. In one or more non-limiting embodiments, the actuator 91 is a nitrogen-backed membrane configured to maintain the sample at the extracted pressure or a selected pressure.

In one or more non-limiting embodiments, the sample capsule 9 includes a sample sensor 92, as shown in FIG. 1, configured to monitor and/or analyze the sample. Non-limiting examples of properties sensed by the sample sensor 92 include temperature, pressure, density, viscosity, and chemical composition. It can be appreciated that the capsule sensor 92 can be implemented by an electronic solid-state microchip in order to fit within the capsule. In one or more embodiments, the sample sensor 92 can implement a flexural mechanical resonator such as a tuning fork in order to measure the density or viscosity of the sample. In one or more embodiments, the sample sensor 92 can implement a spectrometer on the microchip to sense the chemical composition of the sample. It can be appreciated that the sample sensor 92 can include memory to record data from monitoring and/or analyzing the sample in addition to information on the location from which the sample was obtained (e.g. borehole depth) and the environmental conditions it was stored at and went through before capture. It can be appreciated that data recorded downhole by the sample sensor 92 may be used to verify or crosscheck data obtained from further analysis in a laboratory or testing facility. Another advantage is that this data is available as soon as the sample capsule 9 is retrieved.

Once the sample capsule 9 enters the drilling fluid 13, it is desirable for the sample capsule 9 to be able to float in the drilling fluid 13 to insure that the capsule 9 reaches the surface of the earth 3. Depending of the dimensions and materials of the sample capsule 9, a buoyancy device 16 may be coupled to the capsule 9. In one or more embodiments, the buoyancy device 16 may be included in the insulation 18.

In order to prevent the sample capsule 9 from lodging itself on the wall of the borehole 2, the sample capsule 2 has a shape that prevents it from snagging a non-uniform surface of the borehole wall. In one or more embodiments, the sample capsule 9 has a substantially spherical shape. In one or more embodiments, the sample capsule 9 has a cylindrical shape with substantially spherical ends.

Reference may now be had to FIG. 2 depicting aspects of a capsule discharge mechanism 28 in the BHA 7 for discharging the sample capsule 9 into the drilling fluid 13 in the borehole 2. In the embodiment of FIG. 2, the pump 12 pumps the formation sample into the sample capsule 9 via a detachable connector 20. Once the sample capsule 9 is filled, a valve 21 is closed to prevent the sample from escaping. In one or more embodiments, the valve 21 acts as a spring loaded one-way valve to automatically admit a sample that is at a higher pressure than the interior pressure of the sample capsule 9. Once the sample capsule 9 is retrieved at the surface, the valve 21 can then be opened to withdraw the sample for analysis. In one or more embodiments, the pump 12 will pump the sample into the sample capsule 9 such as when the sample capsule 9 includes the nitrogen-backed membrane in the actuator 91 discussed above.

Still referring to FIG. 2, the sample capsule 9 is disposed in a conduit 22 configured to provide a flow path for the drilling fluid 13 to enter and exit the BHA 7. An entry door 23 and an exit door 24 are configured to isolate the conduit 22 during normal drilling operations.

Still referring to FIG. 2, when the sample capsule is to be discharged from the BHA 7, a controller 27 transmits signals to door actuators 25 and 26 to open doors 23 and 24, respectively, and to the detachable connector 20 to detach the sample capsule 9 from the BHA 7. Various embodiments of the signals included electrical signals, pneumatic signals and hydraulic signals. Once the doors 23 and 24 are opened, the drilling fluid 13 will flow through the conduit 22 and eject the released sample capsule 9 from the BHA 7 and into the annulus 14. Once the sample capsule 9 enters the annulus 14, it will be entrained in the drilling fluid 13 and float towards the surface of the earth 3. At or near the surface, the sample capsule 9 will be caught by the sample capsule catcher 15 and then removed from the flow path of the drilling fluid 13.

It can be appreciated that in one or more embodiments, the controller 27 may be configured to delay the release of the sample capsule 9 or to release it at a selected time. Since the sampling may be done when drilling has been halted and the drilling mud may not be flowing, it may be desirable to release the sample capsule 9 when the drilling mud has begun flowing again in order for the flowing drilling mud to urge the capsule 9 to the surface. In one or more embodiments, the sample capsule 9 can be released when the drilling mud is not flowing with the buoyancy of the capsule 9 being able to float it to the surface.

It can be appreciated that a plurality of sample capsules 9 may be disposed in the BHA 7 in order to take multiple samples at the same depth or at various depths in the borehole 2. It can be appreciated that when multiple samples are taken using the plurality of sample capsules 9, the controller 27 may be configured to release the capsules 9 sequentially while the drilling fluid is flowing in order to prevent the capsules 9 from interfering with each other as they flow towards the surface.

In one or more embodiments, when multiple sample capsules 9 are used, the may be disposed in the conduit 22 similar to the embodiment of FIG. 2 where each capsule 9 has its own detachable connector 20 coupled to the controller 27. Alternatively, the capsules 9 may be stored outside of the conduit 20 in a storage rack 30 in the BHA 7 as illustrated in FIG. 3. The rack 30 includes an ejector 31 coupled to the controller 27 and configured to eject a selected capsule 9 from the BHA 7. In one or more embodiments, the rack 30 is configured to change capsules 9 at a filling station (not shown). In one or more embodiments, multiple capsules 9 are connected to separate fill lines via detachable connectors 20.

It can be appreciated that the sample capsule 9 may include an information tag 32 as shown in FIG. 3. The information tag 32, which can be implemented as an electronic solid-state microchip, includes such information as an identification number, location the sampling point, and environmental conditions at the time of sampling. The controller 27 is configured to write this information to the tag 32 using a transducer 33, which can be a wireless transducer.

It can be appreciated that one or more functions of the controller 27 can be implemented by a processing system such as a computer processing system disposed at the surface of the earth. The surface processing system is configured to communicate with one or more downhole components using a telemetry system such as wired drill pipe.

FIG. 4 presents one example of a method 40 for retrieving a downhole sample. The method 40 calls for (step 41) conveying a carrier through a borehole penetrating an earth formation. Further, the method 40 calls for (step 42) extracting a sample from the earth formation with a sampling tool disposed at the carrier. It can be appreciated that the earth formation can represent any downhole material of interest from which a sample is desired to be retrieved. Further, the method 40 calls for (step 43) disposing the sample in a sample capsule. Further, the method 40 calls for (step 44) releasing the sample capsule into drilling fluid in the borehole using a capsule discharge mechanism.

It can be appreciated that the sample can be a fluid, a solid, a solid entrained in a fluid, or a fluid entrained in a solid.

In support of the teachings herein, various analysis components may be used, including a digital and/or an analog system. For example, the controller 27 may include the digital and/or analog system. The system may have components such as a processor, storage media, memory, input, output, communications link (wired, wireless, pulsed mud, optical or other), user interfaces, software programs, signal processors (digital or analog) and other such components (such as resistors, capacitors, inductors and others) to provide for operation and analyses of the apparatus and methods disclosed herein in any of several manners well-appreciated in the art. It is considered that these teachings may be, but need not be, implemented in conjunction with a set of computer executable instructions stored on a computer readable medium, including memory (ROMs, RAMs), optical (CD-ROMs), or magnetic (disks, hard drives), or any other type that when executed causes a computer to implement the method of the present invention. These instructions may provide for equipment operation, control, data collection and analysis and other functions deemed relevant by a system designer, owner, user or other such personnel, in addition to the functions described in this disclosure.

Further, various other components may be included and called upon for providing for aspects of the teachings herein. For example, a power supply (e.g., at least one of a generator, a remote supply and a battery), cooling component, heating component, magnet, electromagnet, sensor, electrode, transmitter, receiver, transceiver, antenna, controller, optical unit, electrical unit or electromechanical unit may be included in support of the various aspects discussed herein or in support of other functions beyond this disclosure.

The term “carrier” as used herein means any device, device component, combination of devices, media and/or member that may be used to convey, house, support or otherwise facilitate the use of another device, device component, combination of devices, media and/or member. Other exemplary non-limiting carriers include drill strings of the coiled tube type, of the jointed pipe type and any combination or portion thereof. Other carrier examples include casing pipes, wirelines, wireline sondes, slickline sondes, drop shots, bottom-hole-assemblies, drill string inserts, modules, internal housings and substrate portions thereof.

Elements of the embodiments have been introduced with either the articles “a” or “an.” The articles are intended to mean that there are one or more of the elements. The terms “including” and “having” are intended to be inclusive such that there may be additional elements other than the elements listed. The conjunction “or” when used with a list of at least two terms is intended to mean any term or combination of terms. The terms “first” and “second” are used to distinguish elements and are not used to denote a particular order. The term “couple” relates to coupling a first component to a second component either directly or indirectly through an intermediate component.

It will be recognized that the various components or technologies may provide certain necessary or beneficial functionality or features. Accordingly, these functions and features as may be needed in support of the appended claims and variations thereof, are recognized as being inherently included as a part of the teachings herein and a part of the invention disclosed.

While the invention has been described with reference to exemplary embodiments, it will be understood that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications will be appreciated to adapt a particular instrument, situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. 

1. An apparatus for retrieving a downhole sample, the apparatus comprising: a carrier configured to be conveyed through a borehole penetrating an earth formation; a sample capsule configured to be disposed at the carrier and to contain the sample; and a capsule discharge mechanism configured to discharge the sample capsule downhole into drilling fluid in the borehole.
 2. The apparatus according to claim 1, wherein the sample capsule comprises insulation configured to insulate the sample.
 3. The apparatus according to claim 1, wherein the sample capsule comprises a buoyancy device configured to add buoyancy to the sample capsule in order for the sample chamber to float in the drilling fluid.
 4. The apparatus according to claim 1, wherein the sample capsule comprises a sample sensor configured to sense one or more properties of the sample.
 5. The apparatus according to claim 1, wherein the sample capsule comprises an actuator configured to actively maintain a selected environment in the sample capsule.
 6. The apparatus according to claim 1, wherein the sample capsule comprises a substantially spherical shape.
 7. The apparatus according to claim 1, wherein the sample capsule comprises a cylindrical shape with spherical ends.
 8. The apparatus according to claim 1, wherein the sample capsule comprises a material having a wall thickness sufficient to withstand a pressure at which the sample was retrieved from earth formation.
 9. The apparatus according to claim 1, wherein the sample capsule comprises a valve configured to admit and/or discharge the sample.
 10. The apparatus according to claim 9, wherein the valve is configured to admit the sample into the sample capsule when a pressure of the sample is greater than an interior pressure of the sample capsule.
 11. The apparatus according to claim 1, further comprising a pump configured to pump the sample into the sample capsule.
 12. The apparatus according to claim 1, further comprising a bottom hole assembly (BHA) having a sample tool configured to extract the sample from the earth formation and dispose the sample in the sample capsule.
 13. The apparatus according to claim 12, wherein the BHA comprises a conduit configured to guide the sample capsule out of the BHA and into the borehole.
 14. The apparatus according to claim 13, wherein the BHA is configured to flow a drilling fluid disposed in the borehole thorough the conduit to eject the sample capsule from the BHA.
 15. The apparatus according to claim 12, wherein the sample capsule comprises a detachable connection configured to detach the sample capsule from the sample tool.
 16. The apparatus according to claim 15, further comprising a controller configured to actuate the detachable connection to detach the sample capsule from the sample tool.
 17. The apparatus according to claim 16, wherein the sample capsule comprises a plurality of sample capsules.
 18. The apparatus according to claim 16, wherein each sample capsule in the plurality of sample capsules is configured to be ejected sequentially by the controller.
 19. The apparatus according to claim 1, wherein the sample capsule comprises an information tag comprising identification.
 20. The apparatus according to claim 1, further comprising a capsule catcher disposed at the surface of the earth and configured to catch the sample capsule from drilling fluid flowing out of the borehole.
 21. The apparatus according to claim 1, wherein the carrier comprises a drill string or coiled tubing.
 22. A method for retrieving a downhole sample, the method comprising: conveying a carrier through a borehole penetrating an earth formation; extracting a sample from the earth formation with a sampling tool disposed at the carrier; disposing the sample in a sample capsule; and releasing the sample capsule into drilling fluid in the borehole using a capsule discharge mechanism.
 23. The method according to claim 18, wherein releasing comprises actuating a releasable connection coupling the sample capsule to the sampling tool.
 24. The method according to claim 18, further comprising retrieving the sample capsule from the borehole. 